1. Field of the Invention
The present invention relates to a method and system for transporting frame relay packets of data over satellite or wireless communication links, and, in particular, to a method and system employing a robust, flexible frame format to efficiently transmit data under varying link and data traffic conditions.
2. Description of the Related Art
Transport of frame relay packets over satellite/wireless links introduces a number of technical issues that are not present in terrestrial wireline links. First, satellite/wireless links tend to be much more noisy than terrestrial wireline links. Consequently, satellite/wireless links require the use of error correcting techniques. Second, the bandwidth on a satellite/wireless link is a scarce resource. In the event of data traffic congestion, consideration must be given to the priority of the data being transmitted, with high priority traffic being given preference over low priority traffic. Data compression can also be employed to better utilize available bandwidth. Third, unlike asynchronous transfer mode (ATM) cells, frame relay packets are variable length. Thus, the frame formats used to communicate between satellite/wireless terminals need to be able to transport variable length packets efficiently. Fourth, carrying prioritized data over low bandwidth links creates certain problems. Assume that the transmission of a large, low priority packet has just begun. If the link bandwidth is low, then it may take a long time for the packet to transmit. A high priority packet may then have to wait for an intolerably long period of time before being transmitted.
There are no known systems specifically tailored to address the unique issues relating to transport of frame relay packets over satellite/wireless links. Traditionally, frame relay traffic has been transported over satellite/wireless links by directly connecting frame relay switches to satellite/wireless modems without significant processing to ensure efficient and timely transmission of data over the links. Thus, the present use of satellite/wireless links to transport frame relay data can significantly limit the performance of the frame relay networks.